yeast question - keep harvest?

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yeast question - keep harvest?

Postby bredmakr » Tue Jul 02, 2002 3:58 am

Last night I harvested second generation White Labs California Ale yeast from an IPA fermentation. As I suspected there is a flavor profile that tells me I fermented at too high a temp. I call it the gameybrew taste. Is there a more scientific reference for what causes this flavor. My real question - can I reuse this yeast for additional batches if I keep the temp in the right range or is it forever compromised to produce this off flavor? Second, if I age the IPA will this flavor subside?
Thanks!
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I would keep the yeast.

Postby Brewer2001 » Tue Jul 02, 2002 10:49 pm

I have a Wyeast Irish ale 1084 yeast on it's 9th generation and a Wyeast Chico 1056 on it's third generation. Both are getting better and more predictable with each batch. I know that the Irish will have to go soon...good by old friend!
I wash my yeast every two or three batches if I detect sulfur. This helps because I do not brew that often. Give it a try. I taste the yeast after the brew and before and after the wash, you can tell a lot about its condition if you the track record.

Good brewing,

Tom Flanagan
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"Gamey Brew" flavor might be from yeast autolysis...

Postby Mesa Maltworks » Wed Jul 03, 2002 2:18 am

This gamey flavor you are describing is most likely caused by byproducts that dead yeast are pumping into the brew. If your IPA is high in gravity and fermented under warm (>75) conditions, this could be one cause. Another common cause is using yeast pitches from prior batches from the primary fermenter. Yeast harvested from the primary contains a large proportion of dead, unviable or partially viable cells, none of which you want in subsequent brews. There is also a large amount of proteins and vegetable matter in it as well which can increase the chance of infection of the next batch. Yeast is best harvested from the secondary because of natural selection. The yeast that settles in the secondary were still active at transfer and represent the healthiest population.

I would not use this yeast again as it is risky given the info you have provided. It's re-use would most likely result in an under-pitch due to a low proportion of viable cells. Remember... the quantity of the slurry used is irrelevant... what is relevant is the concentration of viable cells within a volume of pitch.

Techniques like yeast washing are useless in cases like this because it does nothing to increase viability, it simply washes away debris.

Acid washing is also useless because bacteria is most likely not the culprit. Besides... acid washing should only be used when a new culture is not available. The reason for this is that the low pH stresses the yeast, even killing some cells, and therefore reduces viability as well.

Try a new pitch and keep your fermentation temperature at or below 72 deg. F.

Eric
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thanks !!

Postby bredmakr » Thu Jul 04, 2002 3:53 am

as always thanks for the input.
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